Google today outed new updated for Gmail for Android with new features like Pinch-To-Zoom and Swipe Gestures. Earlier couple of Months ago Android Police leaked Gmail 4.2 for Android users but later they withdrawn links due to request from Google.
If you already updated or recently updated your App and can’t see pinch to zoom functionality than you need to activate it by going into Settings of Gmail App. Along with Zoom feature it also include the new swipe gestures, the app now has the ability to “auto-fit” a message to your phone’s screen also.
Currently this new update is available for Android 4.0+ devices. So guys out with old versions are out of luck.
You can find out update over the Google Play Store.